Update README.rst with a link to second behavior issue

Author: m-aciek

README.rst

@@ -5,8 +5,8 @@ DateType
 A Workaround
 ------------
 
-DateType is a `workaround for this
-bug <https://github.com/python/mypy/issues/9015>`_ to demonstrate that we could
+DateType is a workaround for `two <https://github.com/python/mypy/issues/9015>`_
+`bugs <https://github.com/python/mypy/issues/10067>`_ to demonstrate that we could
 have a type-checking-time wrapper for ``datetime`` that doesn't change (or almost
 doesn't change) the implementation, but fixes up two very annoying behaviors of
 the stdlib ``datetime`` module: